Who is Susie and Meggie Kelly from One Thousand White Women and what is their importance?

Susie and Meggie Kelly were identical twins with identical Irish brogues and a penchant for crime. Abandoned as babies, the girls were left in an Irish Catholic convent, which they ran away from when they were ten-years-old. The twins joined the brides program to escape a prison sentence for prostitution and grand theft. They are described as witty, street-wise and clever. Their Cheyenne husbands, who were also twins, commit the final act of savagery that turns the white brides against the tribe.